Is it possible to theoretically determine a battery's amp-hour ratings?

I have been asked to determine the Amp-Hour capacities of a competing battery technology that is not yet released. I'm a bit stumped. I didn't think this was possible. I always thought this was a calculation that had to be determined empirically, but a coworker is insistent that it can be done. Does anyone know how you would take an overall capacity rating (in A-hr, assumed to be the 100-hr rate) and determine the 10hr, 5hr, etc rates? Is this even possible?

Edit: I should note that this is a lead acid battery under investigation.

I don't see why not. An amp hour is equal to one amp of current for an hour (I think?). An amp is one coulomb per second, so we would need 3600 coulombs of electrons. A coulomb is equivalent to 6.2410^18 electrons.

Assuming we know the chemical reaction that occurs, we could calculate the mass of material required, or vice versa.

That being said, battery reactions are not linear, and it will get much more complicated, because the rate of reaction will decrease as it gets closer to equilibrium.